Roy races to the fire hall 30 yards up the street to bring the rescue truck, which holds oxygen and a defibrillator. The survival rate for cardiac arrest victims outside a hospital is low — only 5 to 10 percent live. But if ventricular fibrillation (V-fib) has caused the arrest and if good emergency medical help can restore heart rhythm within 30 minutes, the survival rate rises to 30 percent.

Without oxygen, though, the brain begins to die within five minutes. They have to start cardiopulmonary resuscitation. But there’s a catch: Successful CPR treatments rarely, if ever, last longer than 45 minutes. It is 4:57 p.m. What these first responders don’t know is that they have until 5:42 at the latest to stabilize Howard Snitzer and get him to the Mayo Clinic in Rochester, the nearest hospital capable of handling such a serious case.

“We got to get him inside,” Al says to Koehn. He hoists Snitzer up under the armpits while she grabs his cold, bare legs. Together, they frog-step the heavy stranger into Don’s Foods.

*4:59 — 43 minutes left: Goodhue EMT Jeremy Schafer ambles into the store. He has just parked the school bus he drives and is about to buy buns for dinner. “When I walked in, I got a big surprise,” he says. “Right there, in the first aisle, next to the peanut butter, I see Al and Candace working on this guy.” Schafer immediately joins them.

5:00 — 42 minutes left: Roy pulls the truck up in front of the store and rushes inside carrying the oxygen tank and the defibrillator. Most people think cardiac arrest means the heart just stops. But sometimes it means a heart is beating too fast or erratically — that is, fibrillating — thereby preventing the ventricles from pumping blood to the lungs. The only way to save a victim is to stop the fibrillation. Al grabs an Ambu bag, a manual oxygen pump, and places it over Snitzer’s mouth and nose. With oxygen flowing, they start chest compressions to force it into his lungs and, they hope, through the bloodstream and to his brain. They are doing the job Snitzer’s heart can no longer perform.

5:01 — 41 minutes left: Now hooked up to the defibrillator, Snitzer lies vulnerable and inert. For a moment, CPR stops, and the first shock from the defibrillator shakes his body. His heart flutters — but fails to sustain a regular beat, so they resume CPR.

5:02 — 40 minutes left: Sirens are blaring outside — it’s the other Goodhue fire department regulars, soon to be followed by EMTs and paramedics from nearby Zumbrota and Red Wing. They will all be needed. CPR is often too physically exhausting for one person to perform alone for an extended period. The required pace is an unrelenting 100 chest compressions per minute. Each push must be fast, deep, and hard. The responders will each go for two minutes until their hands cramp and their muscles ache, then someone else will jump in. One by one, 23 men and women will take their turn. Snitzer finally encounters a little luck: Many of the first responders are either home or returning home. Had he suffered his heart attack a few hours earlier, they would have been at work.